Process of uniting vitreous pieces



, such as glass,

plicationof s quantities that will surfaces.

fluidity of the other-Wis solution 'and The pieces to be heated prior to th said synthetic resin thereto ture of about 80 degrees C. surfaces have been coated, as

' and before they are anaintained at a' t film of said synthetic resin. iji Under certain conditions, in lieu of disji-solvin'g the 'said synthetic resin, 'thetic resin may Patented May 8, 1928: i

uNiT o STAT BERNARD LONG, 01 PARIS, FRANCE,

' IAGTURES IDES GLAGES & PBODUI CIBEY, OI PARIS, FRANCE.

ABS TS CHIMIQUES DE SAINT-GOBAIN, CHAUNY &

11mm; or trauma vrrnnous macas Io Drawing.

My invention has for its object to rovide ,means whereby pieces of vitreous so may be united, without the apuch heat asvto cause the weld ing of the pieces, with the production of a joint having greater tensile strength than that of glass itself. I have discovered that this can be accomplished by the proper of a synthetic resin such as a phenol and formaldehyde condensation product, for stance bakelite.

' In carrying out my invention, the surfaces e joined are carefully finished to -"fit one against-the other .throu made. However, in I avoid polishing th faces should be rel found that a surfa with the finest eme hereinafter descri surface finished I paint the two a solution of a phenol and fo product, for in'st suitable solvent such as cohol, or acetone, ferred. The sol trated one so th forms 60 to 80 applied by a ghout the joint to e same, although the s ethyl or methyl at the said synthetic re per cent thereof, and may This tempe to a tempe united, they should emperature of about Application lied mu stance,

so finishing the surfa atively smooth. I have ce produced by grinding ry is suitable forthe joint bed, .whereas a polished with rouge is not suitable. surfaces so prepared with synthetic resin suchtas a rmaldehyde condensationance bakelite dissolved in a etc., the former being preution should bea concenspatula and at a temperature from m degrees C. and in the smallest completely cover such rature increases the e viscous concentrated rmi ts thinner spreading. joined should themselves e application of the and after the before stated,

elgrees C. for some minutes .to drive off the vent, leaving on each surface only a thin the said syn v be rendered fluid by the 'j i aid of heat-alone and applied in this state,

-i .but the process first above indicated proh ary 12, 1920. sea in. 80,838.

the film .thereby produced is thinner. The surfaces thus coated are now brought together under a high pressure,'for instance a pressure amountlng to 5 kilograms 'per square centimeter, and while under this pressure the joint so made is heated, the use degrees C., which temperature is maintained for several days, after which the pieces are allowed to cool slow-1y;

A joint produced as above is character ized by the fact that the two parts of glass are brought into such close contact one with the other that apparently theirsurfaces are, in actual contact, the eyebeing unable to see the joint between them, the pieces being seemingly homogeneous with each other.

Such film of said synthetic resin as exists between the surface is so thin that'the several particles forming it are in adhesion to the opposite glass surfaces so 'that the strength of the joint is not limited by cohesion of said synthetic resin partic es as is shown by the fact that a joint made as above described has a tensile-strength per ces tensile stren b or square centimeter of sin the glass itse f, w ereas said synthetic resin be has a tensile stren th less than the glass. Thus the limiting ictor in the stren th of this joint is the adhesion between sai synthetic resin and glass and not the cohesion of the said synthetic resin to said synthetic transparent and col that the said syn viewed in substantial thickness is colored.

Having thus described my invention what I desire to claim and ent is: 1. A which faces to be joined, andeproducing thereon a smoothness such as produced by grinding "with fine emery, applying tothe said surfaces while hot-a thinfilm of thetic resin such as a phenol and formalde-. hyde condensation product, for instance, and uniting the surfaces under pressure and orless in spite ofthe fact process of uniting vitreous surfaces 80 eat.

the

R r I' '1 V duces a superior result due to the" fact that temperature being gradually raised to 150 .00.

square centimeter much in excess of theresin. Moreover, the joint is practically' xenon T0 socntrn momma mus mmuthetic resin itself when secure by Letters Patconsis s accurately. fitting the surheated syn- 2. A process of uniting vitreous surfaces fol-inzildehyde condensation product, for inwhieh consists inaccurately fitting the surstance driving by heat the solvent from faces to be joined, and producing thereon said surfaees, and uniting-the surfaces under 10 a smoothness such as produced by grinding pressure and heat.

I with fine emery, applying to the said sur- In testimony whereof I hereunto afiix my I faces while hot a concentrated heated solusignature. r 7. tion of synthetic resin such as a phenol and BERNARD LONG. 

